Line 2 rimmed baking sheet with parchment paper. Preheat oven to 350

Whisk flour, baking soda, salt, cornstarch together in a large mixing bowl until combined. Set aside.

Beat butter, cream cheese, sugar in a bowl until light and fluffy about 4 to 6 minutes. Add egg and vanilla, scraping sides a bowl as needed until blended, about 1 minute

Add dry ingredients to wet ingredients, mixing until well Blended, about 1 minute. Fold in chocolate until just combined.

Portion cookie dough with 2 inch portion scoop about 2 inch apart on to the lined baking sheet.

Bake one sheet at a time, rotating the pan halfway through, total baking time 8 to 10 minutes, or until lightly brown. Transfer cookies to baking rack to cool.